1. Field of the Invention
The present invention generally relates to a wheel support bearing assembly that is assembled under a preloaded condition.
2. Description of the Prior Art
The wheel support bearing assemblies for rotatably supporting a vehicle wheel relative to a vehicle body structure are currently available in numerous types and are generally comprised of outer and inner members rotatable relative to each other and at least one circumferential row of rolling elements operatively interposed between the outer and inner members. Of those wheel support bearing assemblies, the wheel support bearing assembly of a third generation type is also known, in which as the inner member, an inner race is mounted externally on an inboard end of a hub axle.
In the third generation type wheel support bearing assembly, the inner race mounted on the inboard end of the hub axle is fixed in position by means of a staking portion formed in the inboard end of the hub axle. The staking portion is staked against an annular end face of the inner race to hold the inner race axially immovably relative to the hub axle to thereby apply a preload for the purpose of increasing the bearing lifetime and the bearing rigidity. In such wheel support bearing assembly, the control of the preload is generally carried out by measuring the initial axial width of the bearing assembly before the staking portion is staked and the post-staking axial width of the same after the staking portion has been staked, with the use of a dial gauge or a laser end-measuring machine and controlling the applied preload in dependence on the amount of change in width between the initial axial width and the post-staking axial width. See, for example, the Japanese Laid-open Patent Publication No. 2001-050832.
It has, however, been found that the above suggested preload controlling method has some problems. Specifically, not only must the measurement of the width of the bearing assembly be carried out twice, i.e., before and after the staking process, but the use is required of the dial gauge or laser end-measuring machine as a width measuring device. Accordingly, not only are complicated and time-consuming procedures of the measurement required, but also a relatively large variation in measurement occurs in the measurements. For this reason, the cost of measurement tends to increase and the reliability of the measured values tends to be lowered.